A fluorinated resin film is excellent in weather resistance, stain resistance, etc. and thus is used, for example, as roofing material, wall covering material, etc. of a building or construction, such as an outdoor exhibition hall, a sports facility, an agriculture house, etc. (a building or construction using a fluorinated resin film as roofing material, wall covering material, etc., will be hereinafter referred to also as a “film structure building”). However, the fluorinated resin film has high solar transmittance, and when it is used as roofing material, wall covering, etc., the inside tends to be too bright, or the inside temperature tends to be too high. Therefore, it is desired to increase the solar reflectance.
A method for increasing the solar reflectance of a fluorinated resin film may, for example, be a method of kneading a reflective pigment such as mica coated with titanium oxide, titanium oxide, aluminum flake, etc. in the fluorinated resin film, or a method of forming a resin film on the fluorinated resin film by a printing method using a printing ink containing such a reflective pigment.
As the printing ink to be used in the printing method, a composition comprising a fluorinated copolymer wherein the mass average molecular weight and content of functional groups are defined, has been proposed (e.g. see Patent Document 1).